Alternating current (or AC) electrical power can be easily generated and transmitted via distribution conductors or lines, in pure or clean wave form, for energizing many loads or components connected on the lines. The component operation will typically be true and reliable when energized by clean power. When powered by contaminated AC power, the operation of some components can be unreliable.
Of importance to this invention, some components when energized cause feedback signals that differ from the pure AC power, which possibly could return to the power distribution network and contaminate AC power on the entire network, and in turn influence the reliability of operation of other components powered by the same distribution network.
Component generated feedback might typically include harmonic signals of the input power signal. The greatest harmonics problems arise from the odd harmonics, and the greatest problem arise from the lowest or 3rd harmonic, as the higher frequency 5th, 7th, etc. harmonics correspondingly have less current strengths.
Filtering circuits in the power distribution lines can reduce the presence or strength of the harmonic signals. However, the filtering circuit components must absorb the energy of the filtered harmonic signals, which for continuous operation may require making the components of greater size or capacity; and many intended uses may limit the component sizes or weights. Moreover, the filtering circuit could include active components, such as operational amplifiers, or could be comprised of only passive components, such as resisters, inductors, or capacitors. Passive components generally have greater reliability, but also have lesser power capacity; and under sizing or over driving any component could lead to complete circuit failure.
A specific need illustration could involve a commercial passenger aircraft, where a common electrical power network energizes the critical flight and navigational controls as well as the passenger entertainment TV monitors, which create many feedback harmonics. Without effective line filtering circuits, the unchecked feedback harmonics would contaminate the AC power network that could adversely reduce the reliability and even safety of the commonly powered aircraft controls.